Bag for packaging tacky polymeric materials



Aug. 11, 1953 F. R. LINDA 2,648,487

BAG FOR PACKAGING TACKY POLYMERIC MATERIALS Filed July 25, 1947 4 Sheets-Sheet l INVENTOR. FRANK RAYMOND LINDA.

BAG Tuazsz MAcr-uNc ATTO R N EYS.

Aug. 11, 1953 F. R. LINDA BAG FOR PACKAGING TACKY POLYMERIC MATERIALS Filed July 25, 1947 1:72; 2. Low MELTING VVAX-LIKE AOH ESIVE PAPER POLYTHENE; LAYER Furs BUTVL RUBBER.

CLAY COATING CASEIN FILM PAPER RESIN COATING PLVS OR LAYER BUTYL. RUBBER 4 Sheets-Sheet 2 POLYTHENE LAYER PAPER PLYS Burn. RUBBER CLAY COATING PAPER RESIN COATING FRANK RAYMOND LINDA.

BY w

ATTORN EYS.

Aug. 1, 1953 F. R. LINDA BAG FOR PACKAGING TACKY POLYMERIC MATERIALS Filed July 25, 1947 /7 PAPER Ou IMPREGNATED PLYS CLAY COATING BUTYL RUBBER C ELLULOSE ACETATE LAYER ADHESIVE SYNTHETIC. On.

PAPER PLYS BU'IYL RUBBER 4 Sheets-Sheet 3 PAPER On. IMPREZGNATEID Furs CLAY COATING k 9 Eugen-:2

El-[ESJVE CELLU LOSE ACETATE LAYER INVENTOR FRANK RAYMOND LINDA.

ATTO R N EYS.

Aug. 11, 1953 F. R. LINDA BAG FOR PACKAGING TACKY POLYMERIC MATERIALS 4 Sheets-Sheet 4 Filed July 25, 1947 On. IMPREGNATED CLAY COATING PA PER Purs R E 8 B U R L Y T U B VINVI. ORGANASOL On. IMPREGNATED CLAY COATING BUTYL. RUBBER PA PER Furs VINYL. ORGANASOL.

INVEZNTOR.

FRANK RAYMOND LINDA.

ATTO R N EYS.

Patented Aug. 11, 195;

PATENT OF FIJCE BAGTOK- PACKAGING TAGKSC POLYMERIC f MATERIAIIS 1 This-inventiomp ertains' to paperbase lami'n ates espeeially adapted for pachi ng tacly; high -molec ular; polymericmaterials; which are subject tocoltlflow; sucli' as buty-l rubber; and: pertains; more? especially; to multi -walled ormulti-ply paper bags incorporating such laminates asan inner ply for packaging materials-of the char-ac ter aforesaid";

Exti'eme'and serious difiiculti'es have been encountered in devising suitablecontainers for packing and" shipping tacky; molecular, polymeric substances-,1 subject tocold flow: such row example as bntyl ruhber; inasmuch as such: substances are found tbea'dhere to almost every thing; I f such materials are packed: in ordinary paper bags; the paper becomes so firm-lybonded to the polymerie material that it can not be" stripped even tedious manual operations; Without leaving large quantities of the paperflhers embedded in the surface of the polymeric: material;- These paper fibers WhiBha l 6'C8l1-ll10S6* fibers; if left embedded the material; impart highly injurious and' deleterious properties: tofi'nished prodiictsmadiatherefrom: For'example, inlthe case 90f butyll rubbenempl'oyed for making: automobiles tire inner tubes, the" so-embeddeek paper filiers act as wicks in, thezcempleted tube,- permittingwheescape of?airgfromtheinterion and the absorption of; moisture, capillary; action;

from-thmexterionto v tha.interior. of theutuher In. order to remove the adhering'paper fibers-results ing from packmgibutyllrubbercinroirllnary paper or: containers; expensive. organic solvents. such: as: methyl; ethyl: ketone,, are. required, in; additiontoethelabor-expensesandldelays in-yolved, in: so treating the: polymeric: material, as well; as: the; loss;- (lithe-material itself due to;.-soly entz aetiom.

Tiherezappearsto he noepointin; recounting;- the usurious-zunsuccessfuh attempts which have here-,- toforea: been; made to. provide suitable; containers; forf packing-t andi shipping; tacky materials: of, they character ahoyementioned; Suiiicerit tosaythat no: satisfactory; container: ion suchpurposeshas: beem evolved: prion to the present; invention; in so far as I am aware. As a result of my experi. mental? investigations in; relation to n this problem,

I; hare worked out-successful solutions thereofvv along several lines-as; f ollows:

Inaccordance with one modification of; my inventiom: I propose to pack the tacky, high molccular,, polymeric. material, such as butylrubher; in multil-w-all on multi'eplypaper bags-having fon-thejnner-i ply a; paper base laminate consist.- ing: of al layer of paper the; inner or exposed,

' melting; wax lilr e adhesive.

surtaceof which: is: faced witha; thins layer: of: a; non taoky rulber -like polymeric material; such? as: polyethylene, bonded to the paper layer. by. means of an interposed: layer: of a: relatively: low: This inner: layer of; polymerized material must be a substance like: polyethylene which" provides a; smooth, unctuous; surface and hence which separates readily from; the-layerof paper Without: paperv fiber adhering; thereto,- into which: azbloek or" the: tacky, high; molecular, polymeric material, such as; butyl: rubber, may be easily slipped. It mustalsobeztal substanceofsuchnature asat'o be compatible-land miscibl'e voith the butyl rubber or the like; i. e;,. a substance Which;- when permanently incor porated 'therein will' not' impart injuriousaiori deler terious' properties toe the. products. made; there from; such as tire:- inner tubes, gloves, rubber. tubing;- etc. In: addition, it mustabesuficiently: tough; flexible andelastic as not. to: befruptured; cold 'flowof the tacky material, as otherwise: such material would contact and: adhere to the: so-exposed portions: off the:p-aper: base; Boly-= ethylene; also called polythene, has 1 been: fnundi ideally adapt'ed' for such purposes; although; other polymeric substances having the; above:- mentioned characteristicswmay/ be; employed.v

T-he purpose=of thB low-melting, wa-xa-like; adhesive interposed betweenthe paper baseeandrthee inner surfacelayer of the polymeric: layer; such as polyethylene; is temporarilyto :bond the latten to the iormerfol purposes of 'fahricating the bags and packing thebut'y-l rubber or similar sub-- stancestherein. Butyl rubber blocks-01' slabs are: ordinarily packed while at atemperaturesome--- Whattaboveroom temperature, for example; about; to F: After" being packed in multi-ply paper" bags; in acccrd'ance Withthe aforesaid modification of" my invention, the butylrubber will Iciecome"tenaciousl'ylionded to theainnenpoly" thene or equiyalentfiim of the" paper basel'ami nate;,while the elevatedtemperature'of the butyl rubber will" melt the wax like adhesiveof the laminate. sufficiently to: cause the latter tobleed into the paper. base; whereby the-polythcue-filmencased" butyl rubber" slab will; due to cold flow; strip, freely away" from, laminate withoutcarryin'g with it'any'adheri'ngpap'ero fibers, the paper base" acting like ablotter to absorb the adhesive during this; pr0cedure: The result-is a butyl rubber blockencased in the tenaciously adhering polythene film, this combihatibn... becoming thereupon loosely" packed in" theu multi -wall paper. bag; A's abovestated, thepolythene film has inherently a smooth unctuous the paper base of the surface, which slips or slides freely against the paper base from which it has thus been separated, and which at the same time wholly encases and thus prevents the tacky surface of the butyl rubber from contacting and adhering to the paper. Accordingly, for purposes of unpacking, the paper bag need only be slit and the filmencased butyl block dumped out.

In accordance with a second modification of the invention, and one which is alternative to that above described, the inner ply of the multiwall paper bag may again comprise a paper base laminate consisting, in this instance, of a paper base, over the inner surface of which is applied a slack-sized, clay coating, the clay coating being surfaced with a thin, relatively impervious film of a glue-like substance, such as casein, on top of which is applied a surface layer or coating composed of a synthetic hydrocarbon resin, which is compatible and miscible with the tacky, high molecular, polymeric material to be packed. Suitable synthetic resins for this inner surface layer of the laminate are, for example, polystyrene, stylene and polyethylene. As in the previous modification of the invention, the resin employed for the inner surface layer of the laminate must be sufficiently tough, flexible and expansible as not to crack under the cold-flow of the tacky polymeric material, and also such as to provide a smooth unctuous surface into n which the tacky material to be packed may be easily slipped.

The function of the clay coating interposed between the paper base and the inner resinous surface layer of the laminate, is temporarily to bond the latter to the former for purposes of employing the laminate in paper bag manufacture, and subsequently filling these bags with the tacky material, butyl rubber or the like, without rupturing the resinous film and without stripping the film prematurely from the paper base. The function of the impenetrable gluelike or casein surface film on the clay coating is to prevent the resinous inner surface layer when applied from penetrating through the clay coating, and thus forming a bond with the paper base, as otherwise the undesired paper fibers would permanently adhere to the resinous mner surface layer of the laminate.

When a tacky, high molecular, polymeric material, such as butyl rubber, is packed in a container in accordance with this modification of the invention, the tacky material will adhere to the inner resinous layer of the laminate, and will also stretch the same due to the cold-flow of the tacky material and, in so doing, W111 strip the resinous layer of the laminate away from its paper base, owing to the weak bondmg act on of the interposed clay coating, thereby effecting complete separation between the two. As a result of this cleavage in the clay coating, some of the clay coating will adhere to the resin film encasing the tacky material, while some will adhere to the paper base. The portions of the clay coating adhering to the resinous layer, however, as well as the resinous layer itself, are not injurious or deleterious substances as embodied 111 the end products into which the tacky material or butyl rubber is fabricated, the resmous layer because it is of itself a rubber-like substance miscible and compatible with the tacky material or butyl rubber, and the clay coating because it acts as a filler in the end products similar to the other fillers, such as carbon black, calc1um carbonate, etc., employed as filler materials in the manufacture of rubber goods.

When the butyl rubber or other tacky substance packed in the container has thus stripped the inner resinous layer away from the paper base of the laminate, the interposed clay coating material which adheres to the contiguous paper and resin layer surfaces of the thus cloven laminate, will act as a friction-minimizing medium to facilitate the slipping or sliding of the resin layer-encased tacky materal with respect to the paper base. Accordingly, the material may be unpacked by merely slitting the paper bag container and dumping the contents.

In accordance with still another modification of the invention, the inner or exposed surface of the-inner ply of a multi-wall paper bag, has applied thereto a slack-sized clay coating which is impregnated with an oil, preferably a synthetic oil, such as those marketed under the name Ucon oils, by Carbide 8: Carbon Chemicals Corp., for example, its Nos. LB-1l45 (high viscosity) and LB-385 (low viscosity) synthetic oils, or its 50-HB series, which are water soluble. Either type may be employed although I prefer to use the LB or water-insoluble type. The number after the LB designates the viscosity in Saybolt seconds at 100 F. These synthetic oils are polyalkylene-glycol derivatives, and their properties are described in an article entitled New Synthetic Lubricants by J. C. Kratzer, D. H. Green and D. B. Williams, appearing in The Petroleum Refiner for February 1946.

It has been found by employing this modification of the invention, that butylrubber blocks and the like may be easily slipped into the containers, whereupon the synthetic oil-impregnated clay coating serves as a weakly bonded separating and surfacing medium between the tacky material and the paper base. The surface of the tacky material, due to cold-flow, becomes completely coated with the oil-impregnated clay coating which adheres thereto, the cold-flow of the material serving also to cleave to the clay coating, and thus strip the so-coated material;

away from the paper base, in consequence of which the so-coated tacky material slides or slips easily with respect to the paper base, owing to the friction-minimizing action of the clay 'Particles adhering to the paper base and to the tacky material respectively. Thus, the contents may be easily removed by slitting the multi-wall bag and dumping the contents.

This modification of the invention may be improved upon by applying to the opposite or non-exposed surface of the inner paper ply of the bag, a thin, impervious film of an organic material, such as vinyl organasol, cellulose acetate or the like. The purpose of backing the inner paper ply with an impervious film of'this character is to prevent the oil of the oil-impregnated clay coating applied to the opposite surface thereof, from seeping or soaking through the outer paper plies of the bag, and thereby eliminating substantial quantities of the oil from the clay coating, in addition to weakening themulti-ply bag structure by the soaking action of the oil.

In accordance with a still further modification of the invention, the inner ply of the multi-wall bag again consists of a paper base laminate consisting of a thin film or layer of cellulose acetate or similar moisture impervious organic film, which is permanently glued to the paper base by means of a suitable interposed resinous or other suitable adhesive. It has been observed that when blocks of butyl rubber or similar tacky maaccesses thoughthebutyl rubber adheres somewhat to the-cellulose acetate film, neverthelessthe bag maybe slit and the bag material stripped away from the surface of the butyl rubber without tearing the acetate film, and hence without-causing any adherence of'the'film or paper to the butyl-rubber. The cellulose acetate or equivalent film acts as a tough, impervious and moisture-resisting shield between the butyl rubber and the paper, which doesnot tear or crack under the cold-fiowing action of the butyl rubber.

Vast improvement inthis modification of the invention is secured, in accordance with a further feature thereof, by the application to the exposed surface of the cellulose acetate layer, of

a light film or coating of an oil, preferably one.

ofthe water-insoluble synthetic oils. above referred to. Owing to the repellant action of such oils with respect to the surfaces of the butyl rubber, the tendency of the butyl rubber to adhere to the cellulose acetate layer is practically eliminated. Thus, the blocks of butyl rubbermay be'ea'sily slipped into multi-wall bags, in'accord-- ance with this modification of the invention, and the bags as easily unpacked by merely slitting and dumping the contents; The surface film of synthetic. oil isnotinjurious to the tacky material or to: products made therefrom, in addition to being present in negligible amount.

Referring now to the drawings:

Fig. 1 is a perspective view of a block of tacky, high molecular, polymeric material, such as butyl rubber, packaged in a multi-wall paper bag or shipping sack, having sewn ends, in accordance with the invention, one corner of the bag being broken-away to illustrate the multi-ply construction of the bag and the block of butyl rubber or the like packaged-therein.

Fig. 2 is a fragmentary enlarged sectional view through a multi-wall bag in accordance with the first modification of the invention above described, wherein the inner ply of the bag comprises. a paper base laminate having a polythyene or equivalent rubber-like inner surface layer laminated tothe paper base by means of aninterposed low melting, wax-like adhesive, this view also illustrating a portion of the butylrubber block contacting the polythene layer.

Fig. 3 is a view similar to Fig. 2, but illustrating the manner in which the butyl rubber block andadhering polythene layer of the paper base laminate strips away from the paper base of the multi-wall bag upon melting of the wax-like adhesive.

Figs 4 illustrates diagrammatically a method of making multi-wal1 paper bags in accordance with the Figs. and 3 modifications, as well also as in accordance with the remaining modificationsof the invention above referred to and discussedmore in detail below.

Figs. 5 and 6 are enlarged, fragmentary sectional views, similar to Figs. 2 and 3 respectively, but illustrating the modification of the invention wherein'the inner ply of the multi-wallv bag comprises a paper base laminate in which a resinous inner surface layer or coating is weakly bonded to the paper base with an interposed slack-sized clay coating carrying a surface film of an impenetrable glue-like substance such as casein. Fig. 5 illustrates the appearance of the bag when the butyl rubber block is first placed therein; whil'e'Fig. S-illustratesthe subsequent appearance whenthe butyl rubber block and; adhering resin coating have been stripped away from the paper trating the modification of the invention wherein the inner ply 0f the multi-wall' paper bag has applied to its inner or exposed surface, a slack-- sized clay coating impregnated-with a synthetic oil as aforesaid. Fig. '7 illustrates the appearance ofthe-bag and butyl rubber block assembly when the block has been first placed in the bag; while Fig. 8 illustrates the subsequent appearanee when thebutyl rubber blockhas subsequently stripped away from the paper bag by cleavage of the interposed oil-impregnated clay coating.

Figs. 9 and 10- are enlarged, fragmentary sectional views, similar to Figs. 7 and 8, but illustrating? the: further modification of the Fig. 7 construction, according to which the inner or non-exposed surface of the inner paper ply of the bag" isv backed by a thin film of vinyl organasol, cellulose acetate or the like, for pre venting the oil in the clay coating, applied to the opposite surface of this inner paper ply, from.

soaking out into the outer paper plies of the bag. bag and butyl rubber block assembly when the block has been first placed in the bag; while.

10v illustrates the subsequent appearancev when the butyl rubber block is subsequently stripped away from the paper bag by cleavage of the interposed oil-impregnated clay coating.

Figs. 11 and 12 are enlarged, fragmentary, sec- Fig. 11 illustrates the appearance of the bag.

when the. butyl rubber blockis first placed therein, while Fig. 12 illustrates the appearance when the butyl rubber block has subsequently stripped. away from the cellulose acetate layer.

Referring. now toFig. 1, there is illustrated. a:

multi-wall paper: bag Ill, made. up. of a multiplicity. of paper tubes, such as H, i2, i3 and [4,. disposed. one within another, these tubes being closed at the base by a sewn seam I5, the top being left open until the butyl-rubber other material. to be therein, whereupon the top is likewise closed by means of a sewn seamil.

block I 6 or Referring now to the modification of the in-- vention illustrated in Figs. 2 and 3, the inner paper ply Id of the multi-wall bag I2, l3, H5, haslaminated to its inner surface a thin layer H3 of polyethylene or equivalent, thislayer 18' being bonded to the paper layer llby means of an interposed layer is of a relatively low melting,

wax-like adhesive which melts at a temperature slightly below the temperature at which the butyl rubber block is is packed. As above stated,

butyl rubber ordinarily has a temperature of about 125 to 145 F; when packed, so that the wax-like adhesive should have a melting point slightly below this, for example, about to F.

The wax-like adhesive may consist, for example; of a microcrystalline wax, compounded Fig. 9 illustrates the appearance of the.-

the modification of the invenpackaged, has been placed with parafiin oil, for reducing the melting point as aforesaid, and containing, in addition, a tackifier, such for example as picolyte or a similar refined resin, for providing the necessary adhesion between the polythene film and the paper. A suitable microcrystalline wax is one composed of paraffin hydrocarbons, largely of the branched chain type, within the range of about C34H'io to C43Haa.

A suitable formula for such a wax-like adhesive is the following:

Per cent Paraffin oil 1-5 Picolyte or similar refined resin tackifier"- 1-5 Microcrystalline wax (M. P. 120-130 F.) Balance After the butyl rubber block l6 has been packaged in the multi-wall container I2, l3, I4, I8, IS, in the manner illustrated in Fig. 1, the cold-flow of the butyl rubber will cause this material to engage substantially the entire exposed surface area of the polythene layer l8, to which the butyl rubber tenaciously adheres. Likewise, the elevated temperature at which the butyl rubber is packed will melt the wax-like adhesive layer [9, causing the same to bleed or be absorbed into the paper plies I2, l3, l4, whereupon the butyl rubber block l6 encased in the adhering polythene surface layer [8 will strip away from the paper plies l2, [3, I4 in the manner illustrated in Fig. 3. Since, as above stated, the polythene film has a smooth unctuous surface, it will slide easily with respect to the inner paper ply l4, whereby upon slitting the paper plies, the butyl rubber and encasing polythene film may be easily dumped out.

Multi-ply pap-er bags, in accordance with Fig. 1, and employing the inner ply paper base laminate of Fig. 2, may be produced in the manner illustrated diagrammatically in Fig. 4. The paper base laminate may be produced by progressively feeding a continuous strip of the paper base material from a supply roll 2| in engagement with a doctor roll 22, which applies thereto the low melting, wax-like adhesing coating l9 from a transfer roll 23, which latter dips into a reservoir 24 of the adhesive material. At the same time, a continuous strip 25 of the polythene film is fed from a separate supply roll 26 and fed, together with the adhesive-coated paper strip 20, between a pair of compression rolls 2! for producing the laminated material 28, consisting of the paper base 20, the polythene film 25 and the interposed adhesive 19. The laminated material so formed is wound up in the form of a supply roll 29, and transferred thence, as at 30, to the entrance side of a bag tuber machine 3| of standard construction. The laminated material 28 is fed into the bag tuber fron roll 30 as the inner ply of the multi-wall bag the remaining plies, such as I2 and 13, of which are concurrently fed from paper supply rolls, such as 32, 33.

Referring now to Figs. 5 and 6, according tc this modification of the invention, the innei paper ply [4 of the multi-wall bag l2, l3, I4 has applied to its inner surface, a slack-sized double clay coating 34, as explained below, on the inner or exposed surface of which is sprayed or otherwise applied a thin impenetrable film of a glue-like substance, such as casein, upon which in turn is applied a resinous coating or layer 36 consisting of a synthetic resin, which is compatible and miscible with the tacky, high molecular, polymeric material being packaged, for ex ample, the butyl rubber block I6. As above stated, this resinous layer may consist, for example, of polystyrene, stylene or polyethylene.

The slack-sized clay double coating 34 comprises two separately applied clay coatings, a first coating applied directly to the surface of the paper ply, on which first clay coating is superimposed a second clay coating, to which latter the resinous coating or layer 36 is, in turn, applied. For the first clay coating applied directly to the paper ply, a coating in accordance with the following formula is suitable:

Formula I Per cent Talc 60-70 Bentonite 15-25 Defoamer (National Oil Products Co.

#1338: Nopco Defoamer) 3-4 Ammonium stearate 3-4 Casein sizing 5-7 Formula II Per cent Talc -60 Bentonite 15-20 Nopco defoamer (supra) 3-4 Ammonium stearate 3-4 Casein 12-20 This clay coating is likewise applied in aqueous suspension to the previously clay-coated paper in the manner illustrated in Fig. 4 by the elements 22-24 inc. and to the extent of about 15 to 25 pounds per ream of paper.

The interposed clay coating 34, comprising the two coatings aforesaid, forms a weak bonding layer between the resinous layer 36 and the inner ply l4, such that when the tacky material or butyl rubber block I6 is packaged in the container and subsequently cold-flows, the resinous layer 36 will tenaciously adhere thereto and cause the butyl rubber block and resin-encasing layer 36 to strip away from the paper ply [4 by cleavage of the interposed weak clay coating 34, in the manner illustrated in Fig. 6. As shown in this figure, following the cleavage, portions of the clay coating 34 adhere both to the paper ply l4 and to the resinous layer 36, as illustrated at 34c and 34b. This clay coating, being a frangible or powdery material, thereafter serves as a friction-minimizing medium between the inner paper ply and the resin layer to facilitate slippage of one with respect to the other, whereby, upon slitting the bag, the resin layer encased butyl rubber block may be easily removed by dumping. As above stated, the resinous layer and clay coating adhering to the butyl rubber produce no injurious effects in products made therefrom.

Referring now to Figs. 7 and 8, the inner paper ply l4 may have applied thereto a slack-sized, clay coating 38 in accordance with Formula I given above, which is thereupon impregnated with an oil, preferably a water-insoluble, synthetic oil of the character aforesaid, and the butyl rubber block IE or other tacky material packaged in th container as thus formed. Thereupon, the

r" l l .tackylmateriallt will split easilyawayirom the oil-impregnated clayncoati-ng 23.6, as illustrated in Fig-g8.

.ilteferringvnowito Rigel-g and 10, the modification ot'li'igs. 7- nd B'niay 5138 improved upon by applyin tozthe i ner punch-exposed surface of i animpervinllskfilm llao f ch as celluloseqacetate or vinyl organasol. crganasol, which isput zoutqbytheBakelite ,orporation, isobtained by ball-milling .vinylrresin with a plastic zer in a vaporizable :organic liquid carrier, resulting in a suspension Or; emulsion ofltheyinyl particles ,plasticizer saidliqnld carrier. The resulting suspension or emulsion may he applied to the inner jpaper ply of the bag-in the manner-;illnstrated in Fig. 4 by the elements 221% inc. Fol- .lowingsuch application, the vaporizable liouid carrier evaporatesleavi a the resinparticles deposited wont-he paper surface in the form of-a coatingwhich iseured and fused to form .a con tinuous surface film by passingzthe so-treated paperstrip througha hot oven. Another resin "WhiGhJMaY be simil 1 applied inplace ofrthe vinyl organasol-is vinyl .butyral, also put out by the BakeliteCorporation. The opposite or exposedsurface of. the inner paper plyll is coated Wll'rhTllhB slack-sized, clay coating the manner described with reference to Figs. 7 and 8, so :that when th gbutyl rubber or equivalentmaterial is initially packageddn the bag, it has thecappearance oft-Fi ;9. The butyl rubber, due to cold flow, subsequently strips awa from the bagby cleaviagzerof-the,double-;.clay;-coating as illus trated in Fig. 10. As above stated, the purpose of backing the inncr paper ply M with the i ipervious organic film la is to prevent the oil .a the clay coating 38 from seeping through into the outer paper plies, such as !'2, l 3.

Referring.- HOW. to the modification of th l-llVCF-J- tion shown inl 'igs. llandlZ, the innerpaper-ply Ill: has permanently bonded-- thereto, by means of alayer 39 :of asuitableadhesive, an inner surface layer orfilmdiiof .CBlllllOSQgElCBlRllfl or the ke. .The cellulose acetate,layeit lilit-orms a tough, impervious film. between the. tackymaterial' ljSan-tl the paperplies .12, i4, iwhichlayer does not crackor break due. to bending of the container ,or cold-flowofi'thepackaged material it. .Asaabove stated, the tackymateriai tornaybe D ha eidrin the. multiewall .bag so formed,;although the. .terialilzfi isiound ,toadhere somcwhat tot lulcse .xaceta-te layer, requiring stripping r remova-l o t-be contents. however by apply the; i er; surface or the ,cel'lulosesacetate thinsmr ce o anoi r ch as asrn cti .01 th har ter aforesaid, lit W111 :"be found that the butyl rubber block or equivalent tacky material will strip cleanly away from. the cellulose acetate layer ll, in the manner illustrated in Fig. 12.

Suitable adhesives for applying the cellulose acetate layer to the paper ply are lacquers, such as Du Ponts #4561, vinyl acetate adhesives, made by the Union Carbide or Bakelite companies; or adhesives made by National Oil Products C o. Also, in place of the cellulose acetate film, other equivalent materials may be employed such as vinyl butyral.

The apparatus diagrammatically illustrated Fig. 4 may, by obvious adaptations, be einpled for making multi-wall bags in accordance van any of the Figs. to 1G modifications, as Well as in accordance with that of Figs. 2 and 3 as above described.

:an, organic i I claim:

1. 'A multi-wall paper bag for packaging tacky, rhig h molecular,polymeric materials, in such mannor that said materialsmay be easily removed from saidbag- -said bag comprising a multiplicity of paper tubes, disposed one within another, said tubes being secured togeth er-atone endthereof to form a c1osur,e,-theinner aper tube cfisaid bag being facedivit-h'a subst 11y. impervious superimposed continuous, non-, acky layer of a tough and flexible polymericsubstance loosely bonded to saidpaper with an interposed bondingmedium of ,low tensile strength such that said polymeric vLlaver beieasilyistripped, from said, paper .tube.

2. A roulti-wa'll paper bagsfor packaging .tacky, high .molecular, polymeric vmaterials, in such manner that :said materials may be easily removed from said bag, said bag comprising a multiplicity ofpaper tr ies, disposed one within another, said tubes beingrsecureid together :at one end thereof to :form .a closure, the inner paper tube of .said bag being faced with a substantially impervious superimposed continuous layerof a tough and flexible-polymeric substance bonded to said paper with an interposedbonding medium :O'fi'lOW strength such'that said layer of polymeric substance may be easily stripped from said inner tube, the exposed surface of saidpolymericilayer being coatedwith an; oleaginous film.

3. A multi-wall. paperbag-for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said bag, said *bagcomprisinga multiplicity of paper tubes, disposed one within anothensaid .tubes being secured together at one endthereof-toform a closure, the inner paper tube of said bag being faced with a substantially impervious superimposed continuous layer of a :tough and flexible. polymeric substance bonded to :saidpaperwith aninterposedlayer of a low melting, wax-likeadhesive having a strength less than that of said layerof polymeric substance, .saidpolymericlayer being adapted to engage :and adhere to said tacky, high molecular, polymeric material, whereby, upon packaging said material while at a temperature above the melt-- ing point of-said adhesive, said material and adhering'polymeric layer will, after packaging, strip away from said inner paper tube.

'4. A multi-wall paper bag for'packaging tacky, high molecular, polymeric materials, in such manner that :said materials '-may be easily re- -moved from said bag, said bag comprising a multiplicity of paper tubes, disposed one within another -said tubes being secured together at one -end-thereof'to"form a closure, the inner paper tube ofsaid bag being "faced with a superimposed continuous, non-tacky layer of a tough and .fiexible polymeric substance bonded to said paper with an interposed layer of a pulverulent bonding medium having a strength less than that of said layer of polymeric substance, said polymeric layer being adapted to engage and adhere to said tacky, high molecular, polymeric material, whereby said material and adhering polymeric layer may be easily stripped from said inner paper tube by cleavage of said pulverulent bonding medium.

5. A multi-wall paper bag for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said bag, said bag comprising a multiplicity of paper tubes, disposed one within another, said tubes being secured together at one end thereof to form an end closure, the inner paper tube of said bag being faced with a superimposed continuous, non-tacky layer of a tough and flexible polymeric substance bonded to said paper with an interposed layer of a relatively Weak bonding agent, said polymeric layer being adapted to engage and adhere to said tacky, high molecular, polymeric material, whereby said material and adhering polymeric layer may be easily stripped from said inner paper tube.

6. A multi-wall paper bag for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said bag, said bag comprising a multiplicity of paper tubes, disposed one within another, said tubes being secured together at one end thereof to form an end closure, the inner paper tube of said bag being faced with a superimposed continuous layer of a polyethylene bonded to said paper with an interposed layer of a low melting, wax-like adhesive having a strength less than that of said layer of polyethylene, said polyethylene layer being adapted to engage and adhere to said tacky, high molecular, polymeric material, whereby, upon packaging said material while at a temperature above the melting point of said adhesive, said material and adhering polyethylene layer will, after packaging, strip away from said inner paper tube.

7. A multi-wall paper bag for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said bag, said bag comprising a multiplicity of paper tubes, disposed one within another, said tubes being secured together at one end thereof to form a closure, the inner paper 1 tube of said bag being faced with a superimposed, continuous layer of polyethylene bonded to said paper with an interposed layer of a pulverulent bonding medium having a strength less than that of said polyethylene layer, said polyethylene layer being adapted to engage and adhere to said tacky, high molecular, polymeric material, whereby said material and. adhering polyethylene layer may be easily stripped from said inner paper tube by cleavage of said pulverulent bonding material.

8. A multi-wall bag for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said bag, said bag comprising a paper tube having a closed end and a further tube of a tough and flexible polymeric substance, said further tube being a continuous, unitary, non-tacky film of said substance and having a closed end and said further tube being disposed within said paper tube and bonded thereto by a bonding medium of a tensile strength less than that of said tubes whereby said further tube may be separated as a unit from said paper tube.

9. A multiwall container for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said container, said container comprising a, tube having a closed end and a layer of a substance which is compatible and miscible with said polymeric materials, said layer being a continuous, non-tacky film of said substance in the shape of a tube having a closed end, said layer being disposed within said first-mentioned tube and being bonded thereto by a bonding medium of a tensile strength less than that of said layer and said first-mentioned tube whereby said layer may be separated as a unit from said first-mentioned tube.

10. A multiwall container for packaging tacky, high molecular, polymeric materials, in such manner that said materials may be easily removed from said container, said container comprising a tube having a closed end and a cellulose fiber free layer of a flexible polymeric substance which is compatible and miscible with said polymeric materials, said layer being a continuous, non-tacky film of said substance in the shape of a, tube having a closed end, said layer being disposed within said first-mentioned tube and being bonded thereto by a bonding medium of a tensile strength less than that of said layer and said first-mentioned tube whereby said layer may be separated as a unit from said first-mentioned tube.

FRANK RAYMOND LINDA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,334,637 Robinson Mar. 23, 1920 1,441,133 Taylor Jan. 2, 1923 1,656,368 Bates et a1. Jan. 17, 1928 2,167,783 Strovink Aug. 1, 1939 2,205,956 Humphner June 25, 1940 2,208,060 Wagner July 16, 1940 2,222,956 Seaten Nov. 26, 1940 2,274,848 Pennell Mar. 3, 1942 2,293,568 Snyder Aug. 18, 1942 2,331,536 Cerf Oct. 12, 1943 2,341,078 Bradley Feb. 8, 1944 2,391,986 Leach Jan. 1, 1946 2,394,616 Knoth et al. Feb. 12, 1946 2,406,660 Brady Aug. 27, 1946 2,420,212 Volksdorf May 6 1947 2,436,596 Noakes et a1. Feb. 24, 1948 2,458,750 Trepp Jan. 11, 1949 2,587,594 Chavannes et a1 Mar. 4, 1952 

1. A MULTI-WALL PAPER BAG FOR PACKAGING TACKY, HIGH MOLECULAR, POLYMERIC MATERIALS, IN SUCH MANNER THAT SAID MATERIALS MAY BE EASILY REMOVED FROM SAID BAG, SAID BAG COMPRISING A MULTIPLICITY OF PAPER TUBES, DISPOSED ONE WITHIN ANOTHER, SAID TUBES BEING SECURED TOGETHER AT ONE END THEREOF TO FORM A CLOSURE, THE INNER PAPER TUBE OF SAID BAG BEING FACED WITH A SUBSTANTIALLY IMPERVIOUS SUPERIMPOSED CONTINUOUS, NON-TACKY LAYER OF A TOUGH AND FLEXIBLE POLYMERIC SUBSTANCE LOOSELY BONDED TO SAID PAPER WITH AN INTERPOSED BONDING MEDIUM OF LOW TENSILE STRENGTH SUCH THAT SAID POLYMERIC LAYER MAY BE EASILY STRIPPED FROM SAID PAPER TUBE. 